Sharpening device



Jan. 22, 1957 H. ROBERTS 2,778,249

SHARPENING DEVICE Filed May 12, 1955- l NV ENTDR HEHBLTRT L. R05RT5 My invention relates to improvements in sharpeners of the kind employedfor sharpening edged tools, such as knives and scissors. More particularly the invention pertains to a kitchen appliance for restoring the cutting edges of knives and the like, although it is not restricted in this respect but may be devised as a sharpener for lawn mowers and other outdoor implements having blades that require to have cutting edges restored from time to time.

The general object of the invention is to provide a sharpener of the kind referred to which is capable of quickly and easily restoring a cutting edge of an instrument by merely stroking the instrument on the sharpening element of the sharpener.

A further object of the invention is to provide an inexpensive but highly eificient sharpener characterised by a floating hardened disc which is supported to cant to one side to bring one of its peripheral edges into sharpening contact with the cutting edge of a tool drawn across it.

A still further aim of the invention is to provide a sharpener of this kind in which the sharpening disc is mounted on a spindle which can be turned to bring a fresh sharpening edge int-o operative position from time to time in order to maintain the efliciency of the sharpener and to prolong its useful life.

Having briefly recounted major objects and advantages of the invention other objects and advantages will appear as the herein disclosed embodiment of a selected form of the invention is recounted in detail.

The selected embodiment of the invention is shown in the accompanying drawing, in which:

Fig. 1 is a perspective view of the sharpener depicting the manner of use of the device in sharpening a blade of a pair of scissors;

Fig. 2 is a cross sectional view of the sharpener taken on line 2-2 of Fig. 1;

Fig. 3 is a longitudinal section of the sharpener taken on line 33 of Fig. 2;

Fig. 4 is a top plan view of the sharpener;

Fig. 5 is an exploded view in perspective of the sharpening disc and its mounting device;

Fig. 6 is a longitudinal fragmentary section of the disc assembly; and

Fig. 7 is a cross section on line 7--7 of Fig. 2.

The invention is essentially characterized by a support provided with a guideway and carrying a hardened steel disc disposed to intercept the guideway and floatingly supported so that it may assume a canting position crosswise of a cutting blade placed in the guideway and drawn along the same to have sharpening contact with respect to a peripheral edge portion of the sharpening disc. The support is shown as a frame 8 of a general U-shaped configuration made up of a front wall 9, a top wall and a rear wall 11.

Said top wall slopes downwardly from the front wall 9 to the rear wall 11, and has a guideway in it. The guide- States Patent 0 2,778,249 Patented Jan. 22, 1957 Way is an aperture 12 which is slotted for the full length of the top wall 10 and extended downwardly to break into the front and rear walls 9 and 11 respectively. The sides of the slotted aperture 12 have flanking guide plates 13 and 14 which rise from top wall 10. The guide plate 14 is inclined away from the companion guide plate for a purpose which will later appear.

The sharpening disc, denoted at 15, is a thin, hardened steel member of a circular configuration (best seen in Fig. 5) which is located within the confines of the frame 8 to reside at the high end adjoining the front wall 9. The disc is centrally apertured as at 16 and loosely mounted on stud-section 17 which is of a sufiiciently less diameter than the hole 16 as to provide free play. The stud section has a stop shoulder at each end and it forms a part of a stud generally indicated at 18. The axis of the stud is contained in a vertical plane substantially parallel to the blade-receiving guideway. The sharpening device is disposed transversely of the blade-receiving guideway and the portion which is uppermost intercepts the guide slot 12.

The disc is free to wabble on the stud section and the spaced stop shoulders permit restricted end play of the disc which enables it to be canted with its upper part inclined toward the front wall 9.

In a preferred arrangement the stud extends through a hole in front wall 9 and the adjacent stop shoulder is conical to provide a frusto-conical surface as denoted at 19 and has an abrupt outer face 20 which abuts the inner face 21 of the wall 9. The section 22 of the stud extends through the hole in wall 9 and beyond this section the stud is reduced to provide an outer end section 23. A knob-forming collar 24 is sleeved on the section 23 to abut the outer face 25 of Wall 9. The stud is axially bored and in the bore there is a headed screw 26 having its head engaged with collar 24 to lock the same in assembled relation. A washer 27 forms the shoulder at the inner end of the stud and is locked in the assembly by a nut 28 on the inner end of the screw. In this arrangement the collar is locked on the stud and is knurled to enable it to be easily turned by hand. The stud is easily turned by use of the collar. Due to frictional contact the disc can be turned by turning the stud. Consequently the angular position of the disc can be changed from time to time as required in the use of the sharpener.

The guideway 12 accommodates a blade of a cutting instrument such as a blade of a pair of scissors, indicated in Figs. 2 and 3. The blade is placed in the slotted aperture to rest against the inclined supporting plate 14 so that the cutting edge is at the proper angle to the sharpening disc. The blade is drawn forwardly across the disc with sufiicient pressure to effect a sharpening action. A number of such strokes are made in this manner as required to effect the sharpening of the cutting edge. In a sharpening stroke the disc abuts the coued element of the stud and is tilted with its upper edge in- .clined toward the front wall 9 and in this canted attitude the high edge contacts the cutting edge of the blade. A finger 29 desirably depends from the Wall 10 to prevent the disc from canting in the opposite direction to the front wall 9. The disc is tilta-ble in one direction only according to this arrangement.

It is desirable to prevent the disc from wabbling from side to side of the stud and to this end there is provided a stop finger 30 at approximately diametrically opposite sides of the stud. The stop fingers 30 are carried by the front wall 9 and project rearwardly from the inner face 21 thereofsee Fig. 7 in particular.

The guide plates 13 and 14 are shown as attachment members and each has a base 13 and 14 respectively by which it is secured to the frame 8 by fasteners 31.

The sharpening appliance insofar as it. has been recounted makes a reference to a single guideway 12; but actually there are several guideways employed. One is shown on each side of the guideway 12 to extend substantially parallel. These additional guideways, indicated at 32, each comprises a slot in the top wall 10 having its ends in the front and rear walls 9 and 11, and intercepted by the sharpening disc 15. These laterally disposed slots accommodate blades of knives and comparable instruments for the sharpening of the cutting edges thereof by stroking the instruments across the disc in the manner already recounted.

The frame 8 is shown as provided with integral side walls 33 having attachment lugs 34 at the base thereof and pierced to receive fastening elements to secure the frame to a supporting surface. In case it is not desired to fasten the sharpener to a support there may be a handle 35 attached to the frame 8 to extend outwardly from a side wall 33.

From the preceding description it will be manifest that the invention provides a very satisfactory and eflicient sharpener. A feature of the construction is that the disc may be reversed when an edge is worn, thus bringing the other edge into use. Furthermore, several discs may be used on the stud if so desired. These and other modifications may be resorted to as coming Within the scope of the invention.

What I claim is:

A sharpening device comprising a frame made up of enclosing walls including a top wall and a frontal wall, said top wall having a slotted aperture presenting a guideway receptive to an edged tool to be sharpened, a stud rotatably mounted in a hole provided in said frontal wall and having a forwardly projecting end, means providing spaced stop faces on said stand, one of said stop faces defining a frusto-conical surface immediately adjacent the periphery of the stand and further defining a radial thrust surface engaging the inner side of said frontal Wall to limit axial movement of the stud in a forward direction, a sharpening disc having a central hole by which it is mounted upon the stud between said stop faces, the hole in the disc being somewhat larger than the diameter of the portion of the stud between said stop faces so that the disc may cant when an edged tool is drawn across the peripheral portion thereof subjacent said guideway, a knurled collar rigid with said forwardly projecting end of said stud for turning said stud and disc, and a pair of abutment elements on said frontal Wall and disposed at diametrically opposite sides of the stud so as to contact the disc in the canted position of the disc.

References Cited in the file of this patent UNITED STATES PATENTS 1,553,276 Watts Sept. 8, 1925 2,186,715 Zimmer Jan. 9, 1940 

